1. Field of the Invention
This invention relates to a recording and/or reproducing apparatus and, in particular, to a recording and/or reproducing apparatus which performs timing control when a recording medium starts feeding or is at rest.
2. Description of the Related Art
Tape-type recording mediums, such as magnetic tapes, are known as a means for recording and/or reproducing signals. Examples of a recording/reproducing apparatus using a magnetic tape include a VTR (video tape recorder) and a DAT (digital audio tape recorder). When changing, for example, in a VTR, from still to normal reproduction, or vice versa, it is necessary to stop or start a capstan motor of the video tape when the rotating head has attained a predetermined rotation phase. For example, when changing from normal to still reproduction, the capstan motor is stopped when the rotating head has attained a predetermined rotation phase, provided that the rotating head is in a satisfactory tracking condition with respect to the track of the video tape. When transition is made from still to normal reproduction, the capstan motor is started when the rotating head has attained a predetermined rotation phase, provided that the rotating head is tracing a fixed position of the track which is oblique to the path of the video tape.
A control system for detecting the rotation phase of the rotating head so as to stop or start the capstan motor in accordance with the detected result involves a time delay variation caused by the mechanical components thereof. To absorb such a variation, a phase adjusting means which consists, for example, of a volume control, is generally provided at an appropriate position.
However, apart from the above-mentioned time delay caused by the mechanical components, the tape starting/stopping characteristics will vary with changes in various environmental factors, such as the power voltage and the load of the capstan motor, and the tape tension. For example, the amount by which the tape overruns after the capstan is stopped, and the rotating-speed rise characteristic when the capstan is started, tend to vary due to environmental changes as mentioned above. Such variations may cause various problems. For example, the tracing position of the rotating head during still reproduction may be shifted from a desired position, or the rise characteristic in tracking may deteriorate when changing from still to normal reproduction.
FIG. 1 is a diagram showing changes in the starting characteristic of a capstan motor due to a variation in the power voltage thereof. It can be seen from this diagram that the time it takes the capstan motor to stabilize at a predetermined speed after starting depends on the power voltage.